The present invention relates to reflex devices and in particular to devices for simulating an infrared image.
Far Infrared Imaging Devices, many of which operate in the 8 to 13 micron spectral region (a region of high transmission through the atmosphere) rely on small temperature differences between the object being viewed and the background as well as any temperature gradations within the object in order to both recognize and determine features within the object itself. These imaging devices are sensitive to the infrared emission associated with the temperature of the object rather than the reflected light as in the case with visible radiation.
For example, a vehicle can appear as an object that is either hotter or colder than the surrounding terrain. The reason is that the thermal heating and cooling rates of a large steel mass are very different from thermal heating or cooling of the terrain. Whether it is hotter or colder will depend on the history of the air temperature, the amount of sunlight, if daytime, and the recent use of the vehicle. Under either condition the vehicle is just as easily identifiable to an infrared imaging device since it is only dependent on the extent of the temperature differences rather than whether it is colder or hotter than the surrounding terrain.
It has been known to provide a decoy or training device which is heated. This heated decoy is necessarily complex and requires an independent energy source. These known decoys do not have provisions for shaping the temperature gradation over its surface to simulate a given target.
Accordingly, there is a need for a simple passive device for simulating an infrared image which does not require an independent heating source or other elaborate apparatus.